Using It Safely
The absolute limits, the common side effects, and the three symptoms that mean stop and get help.
Never combine this with nitrates
Nitroglycerin tablets, sprays, patches and ointments, isosorbide in any form, and recreational nitrites sold as poppers. The combination can produce a sudden and dangerous fall in blood pressure. There is no dose adjustment that makes it acceptable and no interval that makes it safe on the same day.
Who should not take it at all
- Anyone using nitrate medication or recreational nitrites
- Anyone taking riociguat or a similar soluble guanylate cyclase stimulator
- Men who have had a heart attack or stroke in the last six months
- Unstable angina, or angina brought on by sexual activity
- Uncontrolled high or notably low blood pressure
- Severe liver impairment or severe kidney impairment
- A previous episode of non-arteritic anterior ischaemic optic neuropathy
- Hereditary degenerative retinal disorders such as retinitis pigmentosa
- Anyone under 18, and anyone the medication was not prescribed for
Mention these even if they seem unrelated
Alpha-blockers for blood pressure or prostate symptoms. Other treatments for erectile dysfunction or pulmonary hypertension. Antifungals such as ketoconazole and itraconazole. Certain antibiotics including clarithromycin and erythromycin. HIV protease inhibitors. Some seizure medications. Grapefruit juice in quantity. Any supplement marketed for performance, since several have been found to contain undeclared PDE5 inhibitors.
Side effects, in order of how often they turn up
Common and usually brief. Headache, facial flushing, a blocked or runny nose, mild indigestion, some light-headedness on standing. These come from the same vasodilation the medication produces elsewhere in the body, and they generally fade over the first few uses.
Less common. Back or muscle ache, blurred vision, temporary sensitivity to light, a blue tinge to colour vision, dry mouth.
Rare but serious. Priapism — an erection persisting beyond four hours. Sudden loss or reduction of vision in one or both eyes. Sudden hearing loss, with or without ringing and dizziness. Chest pain during or shortly after sex. Each of these is an emergency.
Three symptoms that mean stop and get help now
An erection lasting more than four hours. Sudden change in vision or hearing. Chest pain during sexual activity. Do not wait to see whether any of them passes — call 911 or get to an emergency department.
Sensible practice
- One dose in twenty-four hours, no exceptions and no top-ups
- Under the tongue, dissolved fully — never chewed, never swallowed whole
- Keep drinking light; heavy intake blunts the effect and sharpens the side effects
- Keep it in its original packaging, out of reach of children, away from heat and damp
- Never share it — it was prescribed against your history, not anyone else's
- Tell any other clinician treating you that you take it, particularly before surgery
The thing worth investigating underneath
Erectile difficulty frequently arrives before a cardiovascular diagnosis, sometimes by several years. The arteries involved are among the narrowest in the body, so they register vascular change early. Treating the symptom does not treat that. Know your blood pressure, your fasting glucose and your lipid panel, and take the symptom to your own doctor as information rather than an embarrassment.
Cleared it with yourself?
The prescribing physician makes the final call, and they need the full list.
Safety questions
Often, but it depends entirely which one. Nitrates are an absolute no. Some alpha-blockers need doses separated. List everything on the assessment and let the physician decide.
That is exactly the question the review exists to answer, and it depends on the condition. Sex itself is exertion; if you have been advised to limit exertion, discuss this with your cardiologist first.
Common early on and it usually settles. Water helps. If it persists, ask about a lower strength rather than quietly stopping — the dose is adjustable.
You multiply the side effects and gain very little. Never exceed one dose in twenty-four hours, and never take a second because the first felt slow.
Get It Sorted
One assessment, one physician, one tablet that does both jobs.